Since 1978, multiple reports of opportunistic infections and Kaposi's sarcoma among previously healthy homosexual men, intravenous drug abusers, and hemophiliacs have been reported. An associated acquired defect in cellular immunity has also been described. The etiology of this syndrome is unknown. More recently, we described a similar outbreak of opportunistic infections and Kaposi's sarcoma among previously healthy Haitians. An associated similar acquired defect in cellular immunity was also noted. Homosexuality and intravenous drug abuse was not seen among the Haitian cases. This syndrome among Haitians is strikingly similar to the syndrome of acquired immunity (AIDS) described among gay men and is most likely the same entity. Therefore, a further understanding of this syndrome among Haitians and the identification of risk-factors in this group is essential. Elucidation of these factors is a prerequisite for prevention and may provide a key to understanding the etiology of this syndrome. The first specific aim of this proposal is the identification of potential risk-factors for AIDS among Haitians. Index cases and matched controls will be selected from patients admitted to Jackson Memorial Hospital, the major provider of health care for the Haitians in the Miami-Dade area. Each index case and four matched controls will be examined and interviewed to evaluate the association of such factors as diet, poor sanitation, crowded living conditions, and prior infections with multiple parasites and disseminated tuberculosis with AIDS. Immunologic studies including monoclonal antibody analysis of peripheral-blood lymphocytes will also be performed to determine the extent of the immunologic defect in the normal Haitian population. Since this outbreak of AIDS among Haitians represents the first outbreak of this syndrome among a large heterosexual group, the evaluation of spread of AIDS among intimate contacts and house-hold member is possible. Therefore, our second goal is directed at the evaluation of inter-family spread of AIDS and the identification of immunologic abnormalities among close contacts. The last specific aim is to define the full spectrum of AIDS in Haitians and correlate clinical and laboratory abnormalities with the long-term prognosis.